CVE-2018-10908 in vdsm
Summary
by MITRE
It was found that vdsm before version 4.20.37 invokes qemu-img on untrusted inputs without limiting resources. By uploading a specially crafted image, an attacker could cause the qemu-img process to consume unbounded amounts of memory of CPU time, causing a denial of service condition that could potentially impact other users of the host.
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Analysis
by VulDB Data Team • 05/01/2023
The vulnerability identified as CVE-2018-10908 resides within the Virtual Desktop and Server Management (vdsm) component of Red Hat Enterprise Virtualization, specifically affecting versions prior to 4.20.37. This flaw represents a critical security oversight that enables malicious actors to exploit resource consumption mechanisms within the virtualization infrastructure. The vulnerability manifests when vdsm processes untrusted image inputs through the qemu-img utility without implementing proper resource limitations, creating an avenue for adversaries to manipulate system resources through crafted file uploads.
The technical implementation of this vulnerability stems from inadequate input validation and resource management within the vdsm subsystem. When processing virtual machine disk images, the system fails to enforce constraints on qemu-img operations, allowing attackers to submit maliciously constructed image files that trigger excessive resource consumption. This behavior aligns with CWE-400, which catalogs weaknesses related to resource exhaustion, specifically addressing the lack of proper resource limitation mechanisms. The flaw operates at the intersection of virtualization management and command execution, where untrusted inputs flow directly into system utilities without appropriate sanitization or resource boundaries.
The operational impact of this vulnerability extends beyond simple denial of service conditions, potentially compromising the stability and performance of entire virtualization hosts. An attacker can consume unlimited memory and CPU cycles through carefully crafted image files, leading to resource starvation that affects not only the targeted virtual machine but also other virtual machines and services running on the same host system. This creates cascading effects that can disrupt service availability for multiple users and applications, making it particularly dangerous in multi-tenant virtualization environments where resource isolation is critical for security and performance guarantees.
From an attack perspective, this vulnerability maps to several ATT&CK techniques including privilege escalation through resource exhaustion and service disruption. The attack vector involves uploading malicious disk images through the virtualization management interface, which then triggers the vulnerable code path in vdsm. The exploitation process requires minimal technical expertise and can be automated, making it particularly dangerous for production environments. Organizations implementing virtualization solutions without proper patching measures face significant risk of system-wide degradation and potential data service interruptions.
Mitigation strategies for CVE-2018-10908 primarily focus on immediate patching to version 4.20.37 or later, which incorporates proper resource limitation mechanisms for qemu-img operations. Additional defensive measures include implementing network-level restrictions on image upload capabilities, establishing monitoring for unusual resource consumption patterns, and deploying automated systems to detect and quarantine suspicious image files. Organizations should also consider implementing resource quotas and limits for virtual machine disk operations, along with regular security assessments of virtualization management components. The vulnerability underscores the importance of proper input validation and resource management in security-critical systems, particularly those handling untrusted data through system utilities.